Integrated circuits are widely used in consumer and commercial products. As the integration density of integrated circuit devices continues to increase, it may become desirable to increase the integration density of the conductive interconnections that are formed on an integrated circuit substrate. Moreover, it also may be desirable to provide more efficient processes for forming the high-density interconnections.
High-density interconnections are particularly desirable for integrated circuit memory devices such as integrated circuit Dynamic Random Access Memory (DRAM) devices. As is well known to those having skill in the art, an integrated circuit memory device generally includes a cell array region wherein an array of memory cells is provided, and a peripheral region that provides control and other circuits for the cell array region. In DRAM devices, data is stored by storing charge on integrated circuit capacitors. Accordingly, it may be desirable to integrate these capacitors with the high-density conductive interconnections for the integrated circuit memory device.
As also is well known to those having skill in the art, DRAM devices may use silicon dioxide, silicon nitride and/or other insulators as the dielectric film for the memory cell capacitors. It also is known to use a ferroelectric film, comprising for example barium titanate and/or other materials, instead of a conventional dielectric film. When a ferroelectric material is used for the dielectric film, a non-volatile memory device may be produced. Thus, the ferroelectric film allows a remnant polarization to be stored in the ferroelectric material so that the memory cell can repeatedly switch between two stable polarization states by means of voltage pulses, thereby providing a non-volatile memory device.
In ferroelectric memory devices, it is known to use refractory metal such as platinum for the capacitor electrodes. Interconnections may be provided using a single level or double level interconnection process using different materials from those of the electrodes. See, for example, the publication entitled Highly Reliable Ferroelectric Memory Technology with Bismuth Layer Structure Thin Film (Y-1 Family) to Fuji et al. IEDM, Vol. 97, pp. 597-600, 1997, wherein a double level metal process is disclosed.
Notwithstanding these and other advances, it continues to be desirable to provide high-density, multilevel conductive interconnections for integrated circuit devices and efficient methods of fabricating the same. It is particularly desirable to provide high1 density interconnections for integrated circuit memory devices such as integrated circuit memory devices that use ferroelectric capacitors, and efficient methods of fabricating the same.